The installation of a tile roof involves a variety of technical challenges and problems not encountered during the installation of a traditional shingle roof. Shingles are relatively thin and can be placed almost flat onto the roof decking in overlapping rows, but roofing tiles are thicker and do not tend to lie as flat when overlapping one another. Roofing tiles, therefore, require special installation methods and devices, particularly at roof transitions such as valleys and side walls.
In additional to flat tile, modern roof tiles are made in a variety of sizes and shapes to complement different architectural styles. For example, a traditional S-shaped tile might be used for Spanish style architecture, while a W-shaped tile might be used for a Mediterranean style project. The multitude of shapes available today increases the complexity of the technical challenges and problems when installing a tile roof.
A typical roof includes a solid plywood decking covered by a waterproof underlayment which is then covered by shingles or roof tiles. At roof transitions such as valleys and side walls, an additional device generally known as a flashing must be installed to collect the flow of water and direct it off the roof. A flashing is also installed at head walls, around chimneys, and around pipes and vents penetrating the roof. Because roof tiles, unlike shingles, do not tend to lay flat upon the flashing, specialized flashing styles have been designed to accommodate the peculiar needs of tile roofs.
For a valley transition, a typical flashing style currently in use for tile roofs is called valley flashing. Valley flashing features a series of built-in support ribs or corrugations to provide support for the roof tiles and to create defined troughs to channel water off the roof. Valley flashing resembles corrugated sheet metal.
For a side wall transition, a typical flashing style currently in use for tile roofs consists of a Z-bar and a side wall flashing (also called a tile pan or a wall tray). A Z-bar is a length of sheet metal that is z-shaped in cross section and designed to catch water flowing down the side wall and channel it into the side wall flashing. A side wall flashing is roughly L-shaped in cross section, but, like the valley flashing, it may contain one or more built-in support ribs or corrugations to channel water off the roof.
For roof transitions, generally, a flashing is used to cover the seam between the generally planar roof sections, to prevent leakage. A typical flashing includes corrugations positioned to channel water directly off the roof.
Generally, roof tiles rest upon one another in overlapping rows called courses. At the eaves of the roof, however, the lower edge of the tiles have no other tiles upon which to rest. So, for proper installation, the lowermost edge of the eaves course of tiles must be elevated above the roof decking to the proper angle or pitch. Supports known as eave risers are typically installed along the eaves to elevate the lowermost edge of the eaves course of roof tiles. An example of such an eave riser is disclosed in U.S. Pat. No. 4,418,505 issued to Thompson on Dec. 6, 1983.
Most eave riser designs include holes for drainage and ventilation. Adequate drainage and ventilation is critical to proper installation of a tile roof because the accumulation of water behind and under the tiles can lead to serious and expensive problems such as wood rot, structural failure, and roof leakage.
A typical eave riser is configured for installation along a generally straight eaves and atop a generally planar roof decking and waterproof underlayment. Although the roof decking and waterproof underlayment may be installed upon a pitched roof, it is generally smooth. A series of straight eave risers can be installed, end to end, along the eaves of the roof. At roof transitions such as valleys and side walls, however, the flashing changes the otherwise flat contour of the roof surface, especially when the flashing contains built-in support ribs or other corrugations. In the field, therefore, an installer may need to cut holes in a typical straight eave riser to accommodate the corrugations in a flashing at a roof transition. Such custom fitting in the field is expensive, time-consuming, and may often result in a significant loss of structural capacity at a critical roof transition.
Thus, there is a need for a method and apparatus for elevating and supporting the eaves course of tile at roof transitions where the valley flashing or side wall flashing includes support ribs or other corrugations. Such an apparatus should maintain sufficient drainage and ventilation at the roof transition. Such a method and apparatus should accomplish these goals in a reliable, durable, attractive, low-maintenance, and cost-effective manner.